A cellular communications network has multiple radio transmitters, each broadcasting to a limited region (a cell). The power and frequencies of each radio transmitter or transmitters for a cell must be carefully chosen; if the power is too low, the cells will not overlap causing areas without adequate signal, and if the signal is too strong, there will be interference between cells.
The common practice is to configure the network so that the power is slightly above the desired level. This margin for error allows for the fact that the signal range may be reduced by atmospheric conditions, but is wasteful of power and increases the interference between cells. After configuring the transmitters to follow a coverage plan for each of the cells of the network, the actual coverage of the cells must be measured to check that the received signal power is according to expectations.
The traditional solution is for the network operator to perform “drive tests”. In this traditional solution, dedicated measuring equipment is placed in vehicles which are driven to the most important locations. The results are processed off-line, by comparison to the coverage plan, and adjustments are determined manually for a given cell. A more automated solution is “UE based network performance measurement” where the network collects data about received power level from customer handsets active in the cell. This is much more efficient than drive testing but is much less precise—even after many measurements are taken and averaged. It is able to detect only major changes such as complete loss of power at a transmitter.